The present invention relates to a lens array; a light emitting diode (LED) head including the lens array; an exposure device including the lens array; an image forming apparatus including the exposure device; and a reading apparatus including the lens array.
A conventional LED head is provided with a plurality of LEDs arranged therein, and is used for a conventional image forming apparatus of an electro-photography type such as a printer, a facsimile, and a copier. A conventional light receiving unit is provided with a plurality of light receiving elements, and is arranged therein is used for a conventional reading apparatus such as a scanner, a facsimile, and the likes. A conventional lens rod array is provided with a plurality of rod lenses arranged therein, and is used in the LED head, or in the light receiving unit for forming an image thereon (refer to Patent Reference).    Patent Reference: Japanese Patent Publication No. 2003-341134
In the conventional rod lens array, however, it is difficult to form an image with a high resolution.
In view of the problems described above, an object of the present invention is to provide a lens array capable of solving the problems of the conventional lens array. In the lens array of the present invention, a plurality of lenses is arranged in rows to form a lens assembly member. In the lens assembly member, the lenses with a specific focal length are arranged with a specific pitch in the rows with a specific pitch, thereby making it possible to form an image with a high resolution.
A further object of the present invention is to provide a light emitting diode (LED) head including the lens array; an exposure device including the lens array; an image forming apparatus including the exposure device; and a reading apparatus including the lens array.
Further objects and advantages of the invention will be apparent from the following description of the invention.